Method of cementing whipstocks in well bores



L. c. lKELLY March 14, 1933.

METHOD OF CEMENTING WHIPSTOCKS IN WELL BORES Y Original Filed Nov., l,1929 Znvenfor. Eaurefzce, CT

M NA J @JW y Patented Mar..14, 1933 PATENT Aori-ucla LURENCE C. KELLY,0F BEVERLY HILLS, CALIFORNIA METHOD OF CEMENTING WHIPSTOCKS IN WELLBORES Original application led November 1, 1929, Serial No. 403,968.Divided and this application iiled November 21, 1932.

This invention relates to a method of set.- ting a cutter defiectingtool or whipstock in a well bore, and it is a general object of theinvention to provide an improved method for effectively and securelysetting a whipstock in cement in a well bore.

In drilling wells it sometimes occurs that the bit meets an obstruction,or the lower end of the well bore becomes obstructed by or side-trackedfrom the original bore,

cutting a slanting bore through theside of said origina-l well bore, andthus passing downwardly along one side of the obstruction.

One of the greatest difficulties encountered in the above outlinedpractice resides in planting the whipstock in a properly centered anduprightposition, and in securely anchoring it in that'position so thatit will neither tilt nor rotate when niet by the drill. One commonpractice -for planting and cementing the whipstock in position has beensimply to drop the whipstock in the Vwell hole, and then follow it witha charge of cement, which cement is intended to fill in around the sidesof and under the whipstock to form a substantial foundation 40 therefor.Y

One of the short-comings of the prior practice arises from the fact thatthe whipstock is not positively held in any given position prior to orduring the cementing operation, with the result that it often comes torest and is set atan-undesirable or even inoperative angle. Further,since in the prior practice the cement descends through the mud ladenfluid in the otherwise open bore, it is often extremely diiiicult andSerial No. 643,616.

sometimes entirely impossible to get the charge of cement down throughsuch fluid to the base of the whipstock, with the result that thewhipstock is unanchored and therefore lnefi'ective in the subsequentside-track- 55 ing efforts. It is therefore the primary object of myinventlon to provide a method for anchoring a whipstock in cement insuch a manner as to insure that the whipstock is initially supported inan upright or operative position and maintained in that position duringthe cementing operation, and to deliver the cement in such a manner thatwhen set it will surround the whipstock in a manner to hold it inoperative position during subsequent side-tracking operations. Inaccordance with the present invention, I lower the whipstock to positionin the well bore on the lower end of a pipe string, and then, beforedetaching the whipstock, v force a measured charge of cement downthrough the pipe string and. into and through a communicating passagewayin the whipstock, whence it is discharged under y pressure to the wellbore, filling -in below and well up around the sides of the whipstock.The cement may then be given time to set and harden, after whichconnection between the pipe string and whipstock may be broken withoutdisturbing the position of the latter; or, if there 'is any danger ofthe cement filling in around the top of the whipstock and makingdisconnection of the pipe string difficult, the connection is preferablybroken before the cement has had time fully to set. The pipe string isthereafter raised out ofthe well bore and the side tracking operationsare carried out in the usual manner.

This application is a division of my copending application entitledWhip-stock, filed November 1st, 1929, Ser. No. 403,968,

wherein is disclosed and claimed the specific whipstock hereinafterillustrated and described in connection l with the lmethod claimed inthe present case.

For the purpose of more fully disclosing the presentlinvention,`reference is now directed to the accompanying drawingshowpresent case as a lost tool 11.

ing a whipstock designed for use in the present method, and wherein:

Fig. 4l is a vertical longitudinal section through the whipstock showingit attached to ajpipe string above the obstruction to be avoided; and

Fig. 2 is a detached, plan View looking down on the whipstock proper;and

Fig. 3 is a view showing a whipstock in the lower end of a well bore,and showing the use of a plug for making known at the ground surfacewhen the cement is all out of the whipstock.

In the drawing numeral 10 designates generally the well bore, in thelower end of which is an obstruction, illustrated ,inthe If the occasionrequires, the first operation may consist in filling in cement above thelost tool to form a solid support, indicated at 11a, upon which thewhipstock may rest at its lower end. This cement filling may be taken astypical of any suitable support for the whipstock. The whipstock,generally designated by the numeral 12, is lowered to a positionadjacent support 11a or obstruction 1l, as the case may be, by means ofa string of pipe 13. Where rotary drilling operations are employed, thedrill pipe ordinarily is used for this purpose. The lower end of thedrill pipe is coupled to a'tool joint 14 to which is threaded a carrierfitting 15 for the whipstock proper. The whipstock proper comprises anelongated body which may be rectangular in cross-section, as shown inFig. 2, or of any other convenient. form, lhaving a beveled upper endproviding a slanting drill-deflecting ysur face 17. Carrier fitting l5has a lower tapered end providing a complementary lower slanting surface18 in Contact with surface 17, and the whipstock is supported fromfitting 15 by means of relatively light frangible bolts 19 passingthrough the 'tapered overlapping ends. The bolt heads are preferablycountersunk in the side of the whipstock body so that they will not rubagainst the side of the well bore or the well pipe as the whipstock islowered.

Fitting 15 and whipstock 12 are drilled with a longitudinal circulationbore or passageway 20 forming a continuation of the bore of the rotarydrill pipe. As a manufacturing expedient, though not necessary to theinvention, bore 20 may be extended through the bottom of the whipstockand then closed off at said bottom by a plug 32.

The lower end of fitting 15 is counter'l bored at 24 and tapped to takea sleeve or Onipple 25 which extends down into a correspondingcounterbore 26 in the whipstock andl rests at its lower end upon arubber gasket 27 therein. There is thus provided a cheaply manufacturedfluid tight joint for bore 20 between the fitting 15 and the whip-`stock proper, eliminating the necessity of accurately machining the twoslanting faces 17 and 18.

The whipstock is provided with a lower reduced section 30 drilled'with anumber of lateral circulation holes lor discharge passageways 31 throughwhich fluid in passageway 2O can be discharged around the sides of thewhipstock. These lateral discharge holes, which are preferably, at thelower end of the whipstock body, as shown, are of a total areapractically equivalent to the area of the main vertical passageway 20.It will be seen thatI body 12 may be considered as a hollow whipstock,with discharge passageways 31 leading from hollow 20 to the exterior ofthe whipstock.

The lower section 30 of the whipstock is provided with grooves 34 toprovide for cement keys, when the cementing operation is carried out.

The method of setting the whipstock in cement is as follows: Afterloweringl the whipstock to the desired point near or above obstruction1l or support 11a, as the case may be, by means of the drill stem, aIneasured charge of cement is forced down by water pressure through thedrill stem and circulation bore of the whipstock, and finally outthrough the circulation passages 31 to fill in around the lower end ofthe whipstock, as indicated at 38 in the drawing.

In certain situations a loose fitting plug is sent down on top of thecement charge; and the arrival of the plug at the lower end of thewhipstock and consequent closure of the discharge openings createsback-pressure which is readilj7 noticed at the ground surface and istaken as an indication that the cement charge is properly delivered. Theplug. also prevents the forcing water from driving the cement chargeentirely clear of the whipstock, as it might otherwise do were theforcing operation to continue too long. Figure 3 represents such asituation, plug 50 having been sent down on top cement 38,

separating said cement from the water 52, wh1ch is 'under pressure fromabove.

When the cement has had time to set, the

drill ipe is released or disconnected from the w ipstock by increasingthe downward pressure on the drill stem causing fitting 15, intending toslide downwardly over face 1'7, to shear bolts'19 and sleeve 25,whereupon the drill pipe is lifted clear of the whipstock and out of thewell bore, leaving the whipstock set in the cement. Or, if kthere isdanger of the cement rising above thejupper end of the whipstock andrenderingfinal disconnection of the pipe string from the whipstockdifiicult, said disconnection is preferably made before the cement hashad time fully to set and harden.

The following operations of drilling against the upper deflectingsurface 17 of the whipstock so that the drill is sidetracked about theobstruction are well understood in the art and need no detaileddescription.

No diiculty ensues if the filled-in cement rises above the levelindicated in the drawing to a point above the upper end -of thewhipstock, provided the drill pipe 1s disconnected before the cement hasfully set and hardened, for the bit will merely drill down through thesurplus cement and when it strikes the upper surface of the whipstockwill be turned aside as before.

It will be now seen that I have provided a method for supporting awhipstock in upright or operative position until cemented in, and forsurrounding the lower end of the whipstock with a solid bed of cement.Thus the method provides for accurate placing of the whipstock, as wellas assuring/that it will be solidly set in cement to maintain it in thatposition. Heretofore when it has been endeavored simply to pour cementdown around a whipstock it has been the common experience that thecement will not pass down below the head of the whipstock because of theheavy mud which is entrapped around and below the whipstock. Bydelivering the cement initially under pressure to a point or pointsaroundthe lower end of the whipstock it is assured that the whipstock-is well set, all of the mud around its base being displaced by cement.

The cement first envelopes the lower end of the whipstock and then flowsupwardly around it. Thus the whipstock is given a perfect foundation atits lower end.

It will be understood the drawing and description are to be consideredmerely as illustrative of and not restrictive on apparatus which may beused in connection with the method of thev present invention, and thatsaid invention is to be limited only as defined in the following claims.

I claim:

1. The method of setting a hollow whipstock in a well bore, thatincludes lowering the whipstock to position in the well bore on thelower end of a pipe string, forcing cement down through the pipe stringinto thehollow of the whipstock and thence through openings in thewhipstock to the exterior thereof, whereby the cement surrounds at leasta portion of the whipstock, allowing the cement to set, and thendisconnecting the pipe string from the whipstock, and removing the pipestring, leaving the whipstock set in the cement.

2. The method of setting in a well bore a whipstock having alongitudinal passage4 therein, that includes lowering the whipstock toposition in the well bore on the lower end of a pipe string, forcingcement down through the pipe string and through the whipstock anddischarging said cement near the lower end of the whipstock to the wellbore, whereby the cement surrounds at least a portion of the whipstock,allow.- ing the cement to set, and then disconnecting the pipe stringfrom the whipstock, and removing the pipe string, leaving the whipstockset in the cement.

3. The method of setting a whipstock in a well bore, that includeslowering the whipstock to position in the well bore on the lower end ofa pipe string, forcing cement down through the pipe string into andthrough a longitudinal passage in the whipstock and through lateraldischarge openings leading from said passageway to the well bore nearthelower end of thewhi stock, whereby the cement surrounds t e lowerportion of the whipstock, 'allowing the cement to set, thendisconnecting the" pipe string from the whipstock, and removing the pipestring, leavingthe whipstock set in the cement.

4. The method of setting a hollow whipstock in a well bore, thatincludes lowering t-he whipstock to position in the well bore von thelower end of a pipe string, forcing cement down through the pipe stringinto the hollow of the whipstock and thence through openings in thewhipstock to the exterior thereof, whereby the cement surrounds at leasta portion of the whipstook,

and subsequently disconnecting the' pi e string from the whipstock andremoving t e pipe string, leaving thewhipstock embedded in the cement.

5. The method of setting in a well bore a hollow whipstock havingdischarge o nings from said hollow to the exterior o the whipstock, thatincludes lowering the whipstock to position on the lower end of a pipestring, introducing a measured quantity ofl cement to the pipe string,following said quantity of cement with av plug adapted to slide throughsaid pipe and to hold the pressure in the pipe string above when itreaches la position at the whipstock, forcing said cement and plug downto the whipv stock, and said cement through the whipstock hollow and outsaid discharge open--v ings whereby the cement surrounds at least aportion of the whipstock, and subsequently disconnecting the pipe stringfrom the whipstock and removing the. pipe string, leaving the whipstockembedded in the cement.

6. The method of setting in a well bore a. hollow whipstock havingdischarge ol enings from said hollow to the exterior o the whipstock,that includes lowering the whipstock to position on the lower end of apipe string, introducing a measured quantity of cement to the pipestring, following said quantity of cement with a plug adapted to slidethrough said pipe and to close olf said discharge openings when it iswithin the I whipstock hollow, forcing said cement and plug down andinto the hollow, and said cement out through said discharge openingswhereby the cement surrounds at least a portion of the whipstock, untilsaid plug l seats in said whipstock hollow, allowing the v cement toset, then disconnecting the pipe string from the whipstock, and removingvthe pipe string, leaving the whipstock set n in the cement. 7. Themethod of setting in a well bore a hollow whipstock having dischargeopene ings from said hollow to the exterior of the whipstock, thatincludes lowering the whipstock to position 011 the lower end of a pipe7'15v string, introducing a measured quant-ity ofv .cement to the pipestring, `following said Pquantity of cement with 'a plug adapted toslide through said pipe and. to hold' the pres- Y 'sure in the pipestring above when4 itreaches a positionjat thewhipstock',`V forcingsaidcement and plug down v ,tovthe, whipstock,

and'said cement through the whipstockhollow and out said discharge'openings whereyby the cement surrounds atleasta portion ofthewhipstock, allowing the cement to set, then disconnecting the pipestring from i the whipstock, and removing the pipe string, leavingthe.'v whipstock set in the cement.l

'30' `In witness that I'vclaim the foregoing I t have hereuntosubscribed my name this 31st day of October 1932. .j LAURENCE C. KELLY

